Pituitary hyperplasia in children with short stature and primary hypothyroidism

Radiological evolution of pituitary hyperplasia in primary hypothyroidism and its differentiation from nonfunctioning pituitary adenoma coexisting with primary hypothyroidism

PURPOSE

In a patient with elevated thyroid stimulating hormone (TSH, >50 µIU/ml) with sellar mass, it is crucial to differentiate isolated pituitary hyperplasia (IPH) from primary hypothyroidism coexisting with nonfunctioning pituitary adenoma (PHCNFPA) pre-operatively to avoid unwarranted surgery in the former condition. Here, we describe patients having pituitary mass/enlargement with markedly elevated TSH (>50 µIU/ml) and attempt to find the differentiating features between IPH and PHCNFPA.

METHODS

This is a retrospective study conducted at a tertiary care center. Case records of patients presenting between January 2020 and December 2022 with elevated TSH (>50 µIU/ml) for whom magnetic resonance imaging (MRI) of the sella was available were reviewed. Demographic details, symptomatology, clinical examination findings, thyroid function tests, data on pituitary hormonal excess and deficiencies, MRI findings, and details regarding levothyroxine supplementation were noted. Based on the final diagnosis, the patients were categorized into two groups: PHCNFPA and IPH.

RESULTS

Five and 11 patients were diagnosed with PHCNFPA and IPH, respectively. The median (IQR) age at presentation of patients with PHCNFPA was significantly higher than that of IPH patients [37 (28-60.5) vs. 21 (10-21.5) years, p: 0.002]. A longer duration of hypothyroid symptoms was noted in the IPH group whereas visual field defects and corticotropin deficiency were more frequent and the pituitary lesion size was greater in PHCNFPA. Thyroid function tests were not different between the two groups. The pituitary enlargement in IPH was initially an increase in pituitary height that progressed to symmetrical nipple-, dome- or tent-shaped enlargement. Besides this characteristic enlargement pattern, isointense appearance on T1-weighted and T2-weighted images, homogeneous contrast enhancement, and prompt regression of pituitary lesion with levothyroxine replacement were characteristic of IPH whereas heterogeneous enhancement, cystic/hemorrhagic change, and ≥Knosp III invasion were characteristic of PHCNFPA. Peripheral rim enhancement and Knosp I-II parasellar extension were not uncommon in patients with IPH and did not distinguish it from PHCNFPA.

CONCLUSIONS

The present study reports the radiological evolution of IPH and a unique series of PHCNFPA along with the distinguishing characteristics between them.

Pituitary hyperplasia in childhood primary hypothyroidism: a review

INTRODUCTION

Pituitary hyperplasia following primary hypothyroidism in pediatric age group population is considered rare with reports of unnecessary neurosurgical intervention for this medically treatable condition. Given the paucity of information on this topic, it is timely to provide clinicians with a comprehensive summary of available research.

METHODS

A search of published studies in Pubmed, PsychInfo and Cochrane Database with the terms "pituitary hyperplasia" or "pituitary hypertrophy" and "hypothyroidism" was performed and the results filtered for English language, pediatric (0-18 years) population and CT or MRI confirmed findings. 55 studies met the inclusion criteria. Data for a total of 110 patients with pituitary hyperplasia following primary hypothyroidism were extracted. The study population included 29 males and 81 females (M: F= 0.35:1). Patient age varied from 3 weeks to 18 years with a mean age of 10.22 years.

RESULTS

The most common clinical presentations included growth retardation, constipation and features of myxedema which were present in 78, 36 and 18 percent of children included in our review. Neuroimaging showed the mean (SD) pituitary height being 13.48 mm (4.72 mm). All of the patients achieved resolution of their pituitary mass and clinical as well as biochemical abnormalities 1 to 26 months after initiation of thyroid hormone replacement therapy, with an average time interval of 7.22 months. Our review has tried to delve in the pathophysiology as well as clinical, biochemical and radiological aspects of pediatric pituitary hyperplasia secondary to primary hypothyroidism and provide recommendations for treatment and follow-up. This may help anyone concerned gain a substantial knowledge on this topic.

Pituitary hyperplasia due to Himalayan endemic hypothyroidism

Pituitary hyperplasia due to hypothyroidism can be treated medically. This condition should not be mistaken for adenoma and surgery should be avoided.

Low Growth Hormone Levels in Short-Stature Children with Pituitary Hyperplasia Secondary to Primary Hypothyroidism

Objective. The follow-up of GH levels in short-stature children with pituitary hyperplasia secondary to primary hypothyroidism (PPH) is reported in a few cases. We aimed to observe changes in GH secretion in short-stature children with PPH. Methods. A total of 11 short-stature children with PPH accompanied by low GH levels were included. They received levothyroxine therapy after diagnosis. Their thyroid hormones, IGF-1, PRL, and pituitary height were measured at baseline and 3 months after therapy. GH stimulation tests were performed at baseline and after regression of thyroid hormones and pituitary. Results. At baseline, they had decreased GH peak and FT3 and FT4 levels and elevated TSH levels. Decreased IGF-1 levels were found in seven children. Elevated PRL levels and positive thyroid antibodies were found in 10 children. The mean pituitary height was 14.3 ± 3.8 mm. After 3 months, FT3, FT4, and IGF-1 levels were significantly increased (all p < 0.01), and values of TSH, PRL, and pituitary height were significantly decreased (all p < 0.001). After 6 months, pituitary hyperplasia completely regressed. GH levels returned to normal in nine children and were still low in two children. Conclusion. GH secretion can be resolved in most short-stature children with PPH.